Thimble Required?

[jono6716]

I just got my liner installed in my chimney and have the Tee snout coming through the wall.. Do i need a thimble as well or can I attach my chimney pipe into the liner Tee? I will have Roxul in the area surrounding the Tee with Durock over that..

 

[mol1jb]

What kind of pipe is that? My first thought would be clearances to the wood framing on either side. Single wall pipe clearances are pretty large. And I don't think a wall thimble would solve that. Usually a wall thimble carries class A chimney pipe.

 

[jono6716]

What kind of pipe is that? My first thought would be clearances to the wood framing on either side. Single wall pipe clearances are pretty large. And I don't think a wall thimble would solve that. Usually a wall thimble carries class A chimney pipe.

Its the stainless steel Tee snout coming off the Tee. Its direct off the Tee from the flexible chimney liner.

 

[mol1jb]

And looking at the picture I am looking inside the house? Also kind of puzzled by the siding on the brick chimney. My main concern would be that single wall pipe clearance is 18" from combustible. The wood framing on either side and the siding is definitely too close to the pipe as is.

 

[jono6716]

And looking at the picture I am looking inside the house? Also kind of puzzled by the siding on the brick chimney. My main concern would be that single wall pipe clearance is 18" from combustible. The wood framing on either side and the siding is definitely too close to the pipe as is.

yes the picture was taken inside the house.. Chimney most likely was added after the house was built I figured. I'm guessing the old aluminum siding wasn't removed for whatever reason. I need a better answer then taking out the studs. I can't have 36" with nothing to attach my concrete board to.

 

[begreen]

You need a thimble to protect the studs. Selkirk's is probably the most affordable.
https://www.hearth.com/talk/threads/chimney-passing-a-chimney-through-the-wall.147754/
https://www.hearth.com/talk/threads/wall-thimble.112191/

 

[3650]

I thought you couldn't mix pipe brands?

 

[jono6716]

You need a thimble to protect the studs. Selkirk's is probably the most affordable.
https://www.hearth.com/talk/threads/chimney-passing-a-chimney-through-the-wall.147754/
https://www.hearth.com/talk/threads/wall-thimble.112191/

Could you provide me with an idea of which thimble would be the best? I will be installing stone on top of the concrete board so I don't really want a huge thimble on the front. Is there anything that might work but not result in that? Also, what kind of clearance do I need between the concrete board and the side of the thimble?

 

[begreen]

I thought you couldn't mix pipe brands?

The snout passes through the thimble. It is just 6" round ss pipe, no brand.

 

[begreen]

The thimble creates the combustibles barrier. Cement board can be taken right up to it. Insul-flue provides good protection. It looks like this installation would need one wall unit and one wall thimble.The article link previously posted lists alternatives to this type of thimble. Most require greater clearances.
(broken link removed)

 

[jono6716]

The thimble creates the combustibles barrier. Cement board can be taken right up to it. Insul-flue provides good protection. It looks like this installation would need one wall unit and one wall thimble.The article link previously posted lists alternatives to this type of thimble. Most require greater clearances.
(broken link removed)

So I'm assuming this would be my end goal?

 

[Nick Mystic]

Is your brick chimney lined with a clay tile flue? Is the flue in good shape with no cracks or gaps in the mortar joints? Is your SS flex liner insulated? If the chimney doesn't have a clay tile flue that is in good shape (no cracks or gaps in mortar joints), then you have to have an insulated SS flex liner for fire protection.

As for your question regarding what you can use to replace those wooden studs: One option would be to replace them with a couple sections of steel I beam. Or if you can't get access to that you could use steel pipe like what is used to make supports in basements. With either of these options you could then place a couple of metal studs next to them to use for attaching your cement board.

 

[jono6716]

Is your brick chimney lined with a clay tile flue? Is the flue in good shape with no cracks or gaps in the mortar joints? Is your SS flex liner insulated? If the chimney doesn't have a clay tile flue that is in good shape (no cracks or gaps in mortar joints), then you have to have an insulated SS flex liner for fire protection.

As for your question regarding what you can use to replace those wooden studs: One option would be to replace them with a couple sections of steel I beam. Or if you can't get access to that you could use steel pipe like what is used to make supports in basements. With either of these options you could then place a couple of metal studs next to them to use for attaching your cement board.

Nothing to worry about in regards to the chimney. I just had a liner put in and it wrapped with insulation. I just recently installed the fire retardant studs in the picture. I'm guessing the thimble will be the way to go. I just can't figure out what thimble would work best.

 

[Dover29]

This is my favorite thimble to use. You bolt it right to the side of the chimney and it allows a tee snout to pass right through and comes with the trim ring for a nice look. https://www.rockfordchimneysupply.com/insulated-chimney-thimble-rigid-pipe-connection.php

 

[jono6716]

This is my favorite thimble to use. You bolt it right to the side of the chimney and it allows a tee snout to pass right through and comes with the trim ring for a nice look. https://www.rockfordchimneysupply.com/insulated-chimney-thimble-rigid-pipe-connection.php

Thx man! That might just do the trick.. So it looks like this cuts the clearance down to 1" since mine is an exterior chimney? Says not to put insulation any closer than that so I guess I should leave 1" airspace between this and my roxul?

 

[bholler]

Is your brick chimney lined with a clay tile flue? Is the flue in good shape with no cracks or gaps in the mortar joints? Is your SS flex liner insulated? If the chimney doesn't have a clay tile flue that is in good shape (no cracks or gaps in mortar joints), then you have to have an insulated SS flex liner for fire protection.

The existence or condition of a clay liner has absolutely nothing to do with the insulation requirement for a stainless liner. It all has to do with the clearance to combustibles. In this case it is insulated so it doesn't matter but i just thought i should clear that up.

Nothing to worry about in regards to the chimney. I just had a liner put in and it wrapped with insulation. I just recently installed the fire retardant studs in the picture. I'm guessing the thimble will be the way to go. I just can't figure out what thimble would work best.

Fire retardant is not the same as non combustible those studs cannot be withing the clearance to combustibles range. So any of the thimbles begreen listed will take care of the issue

 

[Dover29]

Thx man! That might just do the trick.. So it looks like this cuts the clearance down to 1" since mine is an exterior chimney? Says not to put insulation any closer than that so I guess I should leave 1" airspace between this and my roxul?

Yeah one inch should be good. I think I read Roxul is fire rated but I would double check on that.

 

[begreen]

Thx man! That might just do the trick.. So it looks like this cuts the clearance down to 1" since mine is an exterior chimney? Says not to put insulation any closer than that so I guess I should leave 1" airspace between this and my roxul?

The thimble gets a box framed opening. No insulation goes in that opening.


The 2" or 1" spacing is for the chimney itself from the building structure. It's common to find this rule violated. That is where the insulated liner comes in. It makes the installation zero clearance.

You must maintain at least a 2 inch air space clearance between interior masonry chimneys (which have any portion of the chimney located within the exterior wall of the building) and combustible materials. Ensure that building insulation, electrical wiring and/or any other combustible materials do not violate the required 2-inch airspace clearance. The minimum air space clearance between exterior masonry chimneys (which have the chimney completely outside the exterior wall of the building, excluding the soffit or corice area) and combustible material shall be at least 1 inch. Do not fill any required clearance space with insulation or any other materials. Ensure that building insulation, electrical wiring and/or any other combustible materials do not violate the required 2" clearance required for a proper installation of Olympia's Insulated Wall Thimble.

 

[jono6716]

Okay guys.. Got the siding removed and here is what i got.. So if i understand everyone correctly i need to build a box 13.75 x 13.75 out of 2x4??.. as i have a 6" liner that was just installed? Install a thimble mounted to the brick and have the 6" liner go through that through the concrete board and connect on my stove pipe there? Please correct me if i'm wrong.

 

[begreen]

Sounds right. Give Rockford a call if there are specific questions, like how long the tee snout should be.

 

[jono6716]

Sounds right. Give Rockford a call if there are specific questions, like how long the tee snout should be.

Thanks begreen! If anyone else has input please post! Thx everyone for the help. I'll get that ordered, get it boxed up and installed.

 

[jono6716]

I do have another question.. this is an older picture so ignore the surrounding area but when my liner was installed the installers stuffed some of the insulation from the insulation wrap around the snout after they connected it to the Tee and then put masonry cement over that. Is this okay or does that need to be removed?

 

[bholler]

I do have another question.. this is an older picture so ignore the surrounding area but when my liner was installed the installers stuffed some of the insulation from the insulation wrap around the snout after they connected it to the Tee and then put masonry cement over that. Is this okay or does that need to be removed?

That is perfectly fine that is how we do it

 

[jono6716]

That is perfectly fine that is how we do it

Thanks bholler! I appreciate all the help. I talked with Dennis at Rockford Chimney supply and I showed him the same pictures I posted on the forum and he agreed that what you guys recommended would work perfectly. I will be placing my order here shortly for the thimble. He said you and begreen are great! I would have to agree! Thx again everyone! i'll post pictures and or questions when i get the thimble.

 

[jono6716]

Got my 13.75" x 13.75" frame all put together last night. I left it removable as I want to have as much room as possible to get the thimble installed. The tracking info shows the thimble should arrive tomorrow so it looks like the weekend will be a busy one!

One question I had is.. I measured my snout last night and it sticks out about 5.25" from the chimney brick. Will this be enough for it to pass through the thimble? Or will the extension pipe that's included with the thimble make up for the distance? 5.25" makes it just behind my rock board it seems so i may need to extend the thimble out a bit as well.